Knob and Tube rewire cost

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runner9
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Knob and Tube rewire cost

Post by runner9 » Sat Feb 24, 2018 7:53 am

Our house was built in 1954 and had a large addition put in on the early 1990s. The original bungalow is knob and tube and we've always talked about having it replaced. K&T is very, very common in our area and considered safe by everyone if undisturbed. I've read people say "must remove or not get insured", etc and that's just not the case here for whatever reason. That said, this is our forever house and 40 years from now I could easily have passed away and my wife still living here--I don't really want 100 year old K & T.

So, I got 6 company names from a friend who's an office person in a building department. Of those 3 do residential. One had no interest if I wasn't gutting out house which I'm not. One is playing phone tag which scares me a bit (all are good on BBB).

The 3rd gave a quote: He spent nearly an hour here. Said the breaker panel needs replaced as there's no room and a few are split breakers which I agree with. Also was real big talking about 2014 codes for grounding. Would replace all the K&T, check everything else. If we want to switch some single outlets for doubles while they're working that's no problem/no extra cost.Will also interconnect the smoke detectors as well as have arc fault and surge protection on the breaker box for whole house protection. Will use plastic sheeting and shop vacs, will not repair holes but will cut drywall out neatly and save the pieces.

Cost is what got me: $12,700. Does that seem reasonable? I usually get 3 quotes for everything but can't get much interest in this project from recommended companies. I've used a electrician working on the side for small jobs but that has hasn't been permitted and he's not interested in a job this big.

We have the money. House is paid off/no debt, have $124,000 in savings so we can easily afford it and I know the house will be much safer after it's done. It just seems like so much money.

Opinions welcome.

TLC1957
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Re: Knob and Tube rewire cost

Post by TLC1957 » Sat Feb 24, 2018 9:07 am

Have you tried HomeAdvisor or Angie's List for other quotes? We had electric work done and the quotes were $6K between high and low. I developed a bid package and had all the contractors bid to the same list so I could compare apples to apples, you may want to do the same. Is your attic and basement open and accessible for them to work, if not that would raise the $$. In the future do you plan to update and or a new kitchen and or finish the basement, if so install a large enough panel now then to have to add a sub panel later.

dbr
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Re: Knob and Tube rewire cost

Post by dbr » Sat Feb 24, 2018 10:07 am

The rule is always to get multiple quotes, at least three. I am not sure why you are having trouble getting more responses.

I would not think that quote for what you describe is crazy. I don't understand K&T being in a 1954 construction. It wasn't used anymore then.

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Sandtrap
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Re: Knob and Tube rewire cost

Post by Sandtrap » Sat Feb 24, 2018 10:21 am

At least 3 quotes from licensed, insured, reputable electrical contractors, all bidding on the same work (apples for apples).

You may be having trouble getting quotes because a "Knob and Tube" rewire is labor intensive and/or work in your area is very busy and fruitful right now and contractors do not want to do that type of project. Or, your particular home is a "tough one".

aloha,
j :D

dbr
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Re: Knob and Tube rewire cost

Post by dbr » Sat Feb 24, 2018 10:27 am

Sandtrap wrote:
Sat Feb 24, 2018 10:21 am
At least 3 quotes from licensed, insured, reputable electrical contractors, all bidding on the same work (apples for apples).

You may be having trouble getting quotes because a "Knob and Tube" rewire is labor intensive and/or work in your area is very busy and fruitful right now and contractors do not want to do that type of project. Or, your particular home is a "tough one".

aloha,
j :D
Probably you are right about the difficulty of the job. I live in a neighborhood of older homes where contractors that want to do work in older homes are plentiful and getting bids is not a problem. I am still trying to understand how a 1954 home can have knob and tube.

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AtlasShrugged?
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Re: Knob and Tube rewire cost

Post by AtlasShrugged? » Sat Feb 24, 2018 12:07 pm

runner....I had a home with knob and tube wiring that I sold in 2007. The cost to replace it then was ~5,000 and my house was not large. Your estimate of 12.7K is probably not terrible....but absolutely, positively get multiple estimates. And yes, you will probably need a new panel box.

Essentially, you are rewiring your entire house. My advice, spend a little extra, and get a bigger panel box than you think you will need and use more breakers (so you distribute load evenly). Especially is this is the place you are going to stay. Do it once, do it right.

What I might also consider is leaving space near your panel for a PowerWall. I personally think this will be a coming thing in a few years as battery cost comes down. It is not quite there yet, but will be, IMO.
“If you don't know, the thing to do is not to get scared, but to learn.”

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MP123
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Re: Knob and Tube rewire cost

Post by MP123 » Sat Feb 24, 2018 12:42 pm

dbr wrote:
Sat Feb 24, 2018 10:27 am

Probably you are right about the difficulty of the job. I live in a neighborhood of older homes where contractors that want to do work in older homes are plentiful and getting bids is not a problem. I am still trying to understand how a 1954 home can have knob and tube.
Same here. I thought Knob and Tube went out of fashion back in the 1920s. 1954 would almost be in the aluminum wiring era, not that it's much better...

I'd get some more estimates but $12.7k probably isn't too far off.

trs23
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Re: Knob and Tube rewire cost

Post by trs23 » Sat Feb 24, 2018 12:49 pm

If this is your forever house and it’s not a safety concern now why not wait for the next housing downturn when labor is plentiful and you can have your choice of contractors?

Why not market time your improvements?

ThatGuy
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Re: Knob and Tube rewire cost

Post by ThatGuy » Sat Feb 24, 2018 1:04 pm

dbr wrote:
Sat Feb 24, 2018 10:27 am
I am still trying to understand how a 1954 home can have knob and tube.
The contractor cheaped out. Homes in my area were built in the early '50s as well, and not only did they have knob and tube wiring (some still do), but orangeburg pipe was installed.
[url=https://en.wikipedia.org/wiki/Orangeburg_pipe]Orangeburg Pipe] wrote:Orangeburg pipe is bitumenized fiber pipe made from layers of wood pulp and pitch pressed together ... The useful life for an Orangeburg pipe is about 50 years under ideal conditions, but has been known to fail in as little as 10 years.
More to the point, $12,700 sounds cheap to me for a full rewire of an existing house. A panel upgrade costs about that in my area.
Work is the curse of the drinking class - Oscar Wilde

SimonJester
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Re: Knob and Tube rewire cost

Post by SimonJester » Sat Feb 24, 2018 1:30 pm

I would ask some questions about how each contractor plans on re wiring the house.
Per NEC Romex is to be supported every 4 1/2 feet and within 12 inches of a box. Ie stapled to the framing members.
So is each contractor going to remove drywall? If so who will be replacing, patching and repainting?

You may be better off just gutting the house, rewiring, adding insulation while you are at it.

I would check your local building codes to see what they require as well. They also might require the walls being opened up to inspect.

I would also take this time to inquire with your utility about a service upgrade as well. Not sure what amperage you are running but now is the time to upgrade.

With a job this big you absolutely need to get multiple quotes.
"They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety." - Benjamin Franklin

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Epsilon Delta
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Re: Knob and Tube rewire cost

Post by Epsilon Delta » Sat Feb 24, 2018 1:31 pm

I expect that some of the smart house technology will significantly reduce the cost of rewiring a whole house sometime in the not too distance future.* If there is no pressing need to do it now it might be worth waiting and see what develops.

* Although it may require waiting for an entire generation of electricians to retire.

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Pajamas
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Re: Knob and Tube rewire cost

Post by Pajamas » Sat Feb 24, 2018 4:20 pm

Is there any real reason to replace it if it works fine? What's wrong with it? Are you having some problems?

I lived in an old house with mostly knob & tube wiring. It did have a modern breaker box and some modern wiring for the kitchen and laundry room and HVAC system and attic fan, but the outlets and lighting in the rest of the house were on the old wiring.

It made me nervous to walk around in the attic with all of the exposed wires but other than that, I don't remember it causing any issues or problems.

I agree that it would be good to wait for a lull in construction in your area if you are determined to replace it, especially since you seem to be having trouble getting someone to do it now.

travellight
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Re: Knob and Tube rewire cost

Post by travellight » Sat Feb 24, 2018 4:47 pm

How big is your house? I would think there would be a difference between a 1200 sf house and a 5000 sf house.

nativenewenglander
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Re: Knob and Tube rewire cost

Post by nativenewenglander » Sat Feb 24, 2018 5:18 pm

We did this three years ago with our bungalow the cost was $13K. We upgraded to 200 amp, ran underground telephone and power to a carriage house 100 feet away and put a 100 amp box there and rewired the whole carriage house into an office and shop. At the same time we added 100 amp box in the attic. I helped the electrician pull wires and took up 1600 sqft of attic boards two layers thick. I thought that was very, very cheap.

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Re: Knob and Tube rewire cost

Post by DrakeSRT » Sat Feb 24, 2018 7:46 pm

I may have missed size of house. You are getting permits correct? If they are rewiring everything and putting in new outlets, hooking up all existing over head lights and ceiling fans the price doesn't sound bad.

The plastic and shop vac sounds good but be ready for a lot more and bigger holes cut out of the drywall than you were thinking. It's all repairable so start looking for a good drywall guy too.

CurlyDave
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Re: Knob and Tube rewire cost

Post by CurlyDave » Sat Feb 24, 2018 10:47 pm

trs23 wrote:
Sat Feb 24, 2018 12:49 pm
If this is your forever house and it’s not a safety concern now why not wait for the next housing downturn when labor is plentiful and you can have your choice of contractors?

Why not market time your improvements?
+1

It isn't broken -- it doesn't have to be fixed right now. Put it on your to do list and wait until there is a recession. You will have more than enough interest when there are more contractors than work. And you will get a better (inflation adjusted) price.

2comma
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Re: Knob and Tube rewire cost

Post by 2comma » Sat Feb 24, 2018 11:54 pm

I think knob-and-tube gets a bit of a bad rap. Except for not having a ground there is nothing inherently dangerous about it. Most of the problems are seen when someone ties new wiring into existing k&t. I have heard but not verified that some insurance companies won't insure it but that doesn't seem to be an issue for you.

If you want new service, like to add more outlets in the kitchen then I'd go for it. If you're fine and dandy capacity wise I'd probably just leave it.

I'd expect to get some drywall dust throughout the house - just plan to deal with it. After any drywall repairs you'll probably have to repaint the room (I've never successfully matched old paint to my liking) so figure on the cost of drywall repairs and painting unless you DIY.

No idea if that is a good price or not. It all depends on your area, the size of the house, the number of runs and changes and difficulty of access. My gut tells me it's probably a fair price, it's a lot of work.

I think you understand that the electrician was emphasizing 2014 code because any circuit he changes or adds will need to be to current code.

On old work there is no requirement to staple the wires inside the walls. On new walls or a tear-out installing walls with nails/screws into studs you can hit the wires, on an existing wall it is assumed this will not happen.
If I am stupid I will pay.

bogglizer
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Re: Knob and Tube rewire cost

Post by bogglizer » Sun Feb 25, 2018 1:07 am

Suggest leaving the K&T for the lighting and only redo the wall sockets. Not likely to over-voltage the lighting, given modern fluorescents.

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Bammerman
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Re: Knob and Tube rewire cost

Post by Bammerman » Sun Feb 25, 2018 10:46 am

My situation is very similar to Pajama's. When we bought our 1925 house with K&T (with upgrades over the years), our insurance company (USAA) had no problems with that at all. We've had no problems with wiring since we bought the house 11 years ago, and as far as I know, the K&T wiring has been faithfully doing its job for the past 93 years. So, my question to the OP would be, "Is it broke?" Because you know what they say about things that ain't broke.

dot00
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Re: Knob and Tube rewire cost

Post by dot00 » Sun Feb 25, 2018 2:44 pm

Bammerman wrote:
Sun Feb 25, 2018 10:46 am
My situation is very similar to Pajama's. When we bought our 1925 house with K&T (with upgrades over the years), our insurance company (USAA) had no problems with that at all. We've had no problems with wiring since we bought the house 11 years ago, and as far as I know, the K&T wiring has been faithfully doing its job for the past 93 years. So, my question to the OP would be, "Is it broke?" Because you know what they say about things that ain't broke.
Funny how this topic is the one to finally get me to join the site after reading for a couple years. I agree with the above - my knob & tube will turn 100 next year and is fine. Previous owner replaced k&t in the kitchen and a bathroom about 25 years ago, but when we remodeled those same rooms 3 years ago we got to undo all the DIY “creativity”. :happy

I say leave well enough alone until you have the opportunity to pair the work with a more extensive remodel. If you are going to go through the hassle, mess, and whatnot you might as well do something more enjoyable to your day-to-day than replacing wiring. :happy We’ve had success doing this over the past few years and have limited the k&t to our 2nd floor bedrooms which don’t put much load on the wiring (led lights, alarm clocks, etc).

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runner9
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Re: Knob and Tube rewire cost

Post by runner9 » Tue Mar 27, 2018 7:50 am

To followup, we're having the house rewired this week. I ended up with three companies actually at my house, the one that's doing it, one that took 3 weeks to show up and that was 2 weeks ago and I still have no estimate, and one who got here and said they don't do rewiring estimates for free. I feel that I tried my best to vet multiple companies.

Yesterday the owner, an employee and an apprentice upgraded the meter socket and panel to 200 amp service. It's an Eaton 200amp 42 space CH breaker panel, I like what I've read about it online. They also ran a copper wire across the basement and outside to 2 new 8 foot ground rods. The Knob and Tube wires are just attached through the front of the panel temporarily so we had full power last night.

They found the AC wire had been trimmed to fit into the breaker so they'll replace the AC wire. Also are for sure replacing a 14 gauge Romex that goes to the kitchen with 12 and adding a junction box to a light socket in the basement that's screwed directly to the joist. I feel like so far they're taking their time, checking everything and that's good.

Today two employees and the apprentice will be back to start checking everything and replacing as needed in the basement and moving up. Now the holes will start, we'll see how it goes.

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Re: Knob and Tube rewire cost

Post by wilked » Tue Mar 27, 2018 9:34 am

If you want any other electric changes, now is the time...

Things to consider -

1) New light switches, new dimmers, or moving light switches
2) Upgrade lights (recessed?), add a light, etc
3) New outlets, or upgrade 'two-prongers' to three
4) Demo out / remove unwanted outlets / outlets in weird locations
5) Misc changes (wire basement lights so all of them come on together with switch, etc)
6) Porch or outdoor lighting
7) "Enable" future electric car charging (upgrading to 200 amp prob all that's needed there)

barnaclebob
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Re: Knob and Tube rewire cost

Post by barnaclebob » Tue Mar 27, 2018 9:58 am

Epsilon Delta wrote:
Sat Feb 24, 2018 1:31 pm
I expect that some of the smart house technology will significantly reduce the cost of rewiring a whole house sometime in the not too distance future.* If there is no pressing need to do it now it might be worth waiting and see what develops.

* Although it may require waiting for an entire generation of electricians to retire.
How so? Energy needs to get from one part of the house to another. Smart switches and a talking speaker aren't going to change that.

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lthenderson
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Re: Knob and Tube rewire cost

Post by lthenderson » Tue Mar 27, 2018 10:17 am

runner9 wrote:
Sat Feb 24, 2018 7:53 am
Cost is what got me: $12,700. Does that seem reasonable? I usually get 3 quotes for everything but can't get much interest in this project from recommended companies. I've used a electrician working on the side for small jobs but that has hasn't been permitted and he's not interested in a job this big.
In my experience, getting three quotes in this kind of economy is much easier to say than to actually do. I'm in the process of trying to get quotes for an entire addition added onto my house and have passed the 18 month mark with only one quote to show for it.

$12,700 doesn't sound unreasonable to me at all for rewiring an entire house without gutting it. It is very labor intensive to do as you have to cut holes and fish everything. It is very dependent on house style and layout for sure with a ranch type house probably being one of the easiest to do and a three story house with finished ceilings throughout being one of the harder ones to do.

Like others said, I wouldn't just be changing it unless forced for insurance or other reasons. I would just replace it room by room as I remodeled the place. Also, even though the one person quoting said they would leave the pieces of drywall behind, patching will be a lot of work and if you aren't doing it yourself, can be pretty tough to find someone willing to come in and do it for you for a reasonable price as well. It gets expensive because whomever is doing it has to come back multiple days for short periods of time to get everything mudded and sanded.

barnaclebob
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Re: Knob and Tube rewire cost

Post by barnaclebob » Tue Mar 27, 2018 10:26 am

lthenderson wrote:
Tue Mar 27, 2018 10:17 am
In my experience, getting three quotes in this kind of economy is much easier to say than to actually do. I'm in the process of trying to get quotes for an entire addition added onto my house and have passed the 18 month mark with only one quote to show for it.
I agree with this. Had to call about 6 or 7 chimney companies for an estimate for a new liner and only got two to come out. One wouldn't do the work required, the other one seems great so far but needs to do a more detailed inspection before bidding. I also need some major foundation work done and only two companies that I know of serve my area for this kind of project, one just blew me off after coming out and the other seems better but still have some work to do with them before getting a bid.

renue74
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Re: Knob and Tube rewire cost

Post by renue74 » Tue Mar 27, 2018 10:33 am

I just did a rewire in an 80 year old house with K&T. We were pulling the walls down and putting up drywall....so we had easy access to the wall studs to put the switches/boxes/wiring in.

I did a ton of work myself....buying the 14/2 and 12/2 wire, plus all the switches, boxes, staples, light/ceiling fan light boxes, etc. And I helped run the wire.

We ran all the home runs back to a new breaker box and then I had a licensed electrician come in and do the box wiring and meter box wiring. They also went back through and dressed the boxes and cleaned up anything I did wrong.

Even with that....it cost about $8000 in total. their time, plus supplies I bought. This is a simple 1600 sq/ft 1-story bungalow with open walls.

It literally took them about 2 days to wire up the breaker box and meter box and clean up. I'm in the wrong business.

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Epsilon Delta
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Re: Knob and Tube rewire cost

Post by Epsilon Delta » Tue Mar 27, 2018 10:42 am

barnaclebob wrote:
Tue Mar 27, 2018 9:58 am
Epsilon Delta wrote:
Sat Feb 24, 2018 1:31 pm
I expect that some of the smart house technology will significantly reduce the cost of rewiring a whole house sometime in the not too distance future.* If there is no pressing need to do it now it might be worth waiting and see what develops.

* Although it may require waiting for an entire generation of electricians to retire.
How so? Energy needs to get from one part of the house to another. Smart switches and a talking speaker aren't going to change that.
Put a relay (or solid state equivalent) in each light fixture or load to control the power at the point of use. Run power from the meter to the loads using whatever topology minimizes the amount of wire. The switches can control the relays using a wireless or low voltage bell wire network. At the very least you lose all the switch loops. It's a huge win for something like a three way switch on a stair well.

In the context of rewiring a house I hope you can see how this would make things much easier.

In a sense the traditional system uses a high voltage, high current, switch loop as a very low band width data path. Separate the control path from the power distribution. This is what happens in car wiring harness into a door. Simplified slightly, Instead of running a wire for each function we now run four wires, two for power and two for control (CANbus). Thus we can put as many different electric devices in the door as we want without having to feed a thick wire harness through the hinge. You can also do things like have the lights remain on for 20 seconds after the door closes without adding more hardware.

I am told that the electric code is actually going the other way, and that every switch must now have power and neutral so the old two wire switch loop is prohibited. That is why we need a generation of electricians to retire.

e5116
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Re: Knob and Tube rewire cost

Post by e5116 » Tue Mar 27, 2018 11:05 am

You're obviously aware they're not going to repair the holes, but just thought I'd note that the cost of drywall + paint can be considerable. It's hard to just paint the section that was cut out as it won't perfectly match the rest of the room (even if you choose the same paint color since it's probably faded slightly over time), so if you want it to look like really clean and nice, you need to paint the entire wall. Since you're doing the whole house, that means painting the entire house. I doubt they'll use the cut out pieces of drywall, probably easier to just do new drywall - it's not very expensive. But certainly the labor of filling holes and painting a whole house can be significant. (You can certainly paint yourself if you're willing and able). Incidentally, I had some wiring replaced when I moved into my house too although it wasn't a total re-wire. Holes were very considerable, which caused my wife consternation upon seeing it, but the painters/drywall guys were efficient and patched things up quickly after (and painted all the rooms too, which took three guys a week of time).

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runner9
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Re: Knob and Tube rewire cost

Post by runner9 » Wed Mar 28, 2018 7:28 am

wilked wrote:
Tue Mar 27, 2018 9:34 am
If you want any other electric changes, now is the time...

Things to consider -

1) New light switches, new dimmers, or moving light switches
2) Upgrade lights (recessed?), add a light, etc
3) New outlets, or upgrade 'two-prongers' to three
4) Demo out / remove unwanted outlets / outlets in weird locations
5) Misc changes (wire basement lights so all of them come on together with switch, etc)
6) Porch or outdoor lighting
7) "Enable" future electric car charging (upgrading to 200 amp prob all that's needed there)
Thanks, so far the company has been great to work with. I think I mentioned that there's an early 90s addition so part is romex already. They are checking every outlet/switch/light and replacing all K&T wiring as well as every single switch and outlet regardless so all will match. We're adding several outlets and changing 6 lights so the hall lights match. They've been careful to make as few holes as possible. From yesterday 2 rooms one the first floor have new rewired outlets, a third has no outlets right now, that's next up. There's a long way to go.

mancuso
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Re: Knob and Tube rewire cost

Post by mancuso » Tue Aug 28, 2018 11:05 pm

Around $12K to $13K is totally reasonable.

My point of reference: serious DIY homeowner (I own & have read all of the relevant Nat'l Electrical Code,) and I completely re-wired my 1200 sq. ft house. Every wall outlet, wall switch, overhead fixture, bathroom vent fan, exterior fixtures, etc. Brand new 225A sub-panel w/ 3/0 AWG feeder cable, Square D QO CAFCI-type breakers, GFCI outlets everywhere (except refrigerator,) all-copper 12AWG MC branch wire, dual-gang deep metal boxes at all locations, etc.

Connections tally:
Overhead fixtures: 11 + 1 bathroom vent/heater combo
Wall switches: 9
Wall outlets (receptacle locations): 40

Average time per wiring location, including removing K&T and poorly-done previous add-ons, cutting plaster / installing boxes / pulling wire, patching/sanding/painting, about 2.5 hours x 61 locations = 152 hours.
Then another 50-60 hours to install a new sub-panel, heavy metal (2.5" diameter) conduit from the main panel, make all the connections, etc.
200 hours total -- if that was done by a pro in my area of urban California they would charge $85 to $100/hour (at least,) -- $17K to $20K before adding cost of materials & wire, which was around ~$3K to $4K.

I did everything to a high standard, i.e. every kitchen countertop outlet is on its own dedicated breaker. Every room is served by (2) x 15A circuits (1 of which can be controlled by a home automation system.) Commercial-grade GFCI outlets (there are differences in quality, think Hubbell vs. consumer-grade Leviton, or worse, no-name Amazon.com chinese imports.) I took an extra 10-15 minutes per location to caulk the boxes with UL-listed flexible fire caulking: very important to seal the box so that air does not flow into/out of the wall cavity, causing draftiness & increasing HVAC bills. (Also has the benefit of making the installation overall more durable & safe** because dust-laden air isn't constantly flowing through the outlet/switch devices.) **Note that this is only safe if using generously-sized metal junction boxes which can easily dissipate any heat-build up through their walls. Plastic / fiberglass boxes require ventilation because they do not conduct heat well.

Even with ideal accessibility (open attic, 6' walk-in crawl space with direct access to every room, all wood-frame construction,) it was a very time-consuming and labor intensive project.
------

The REAL kicker was not the 200 hours of actual labor -- it was the ~80 to 100 hours of extra research / preparation / tools & special parts acquisitions, triple-checking the electrical code to be sure not to buy, or worse yet, install the wrong sort of equipment, breakers, wire, etc. and then not pass inspection. (Having to pull it out & do it over, etc.)

NYnative
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Re: Knob and Tube rewire cost

Post by NYnative » Tue Aug 28, 2018 11:39 pm

I have a simple answer as to why K&T should be replaced sooner, rather than later. It's called fire. My nephew is a fire captain in a town where there are many older homes - some going back 150 years, as well as others built within the last 40 to 50 years (and of course, some really new ones). Our house was built in 1976. It has modern wiring and, prior to buying it, I checked to make sure none of it was aluminum wire.

According to my nephew, electrical fires are far more common in houses with K&T wiring (or aluminum wiring) than those with modern, grounded circuitry and 200 amp panels. By far more common, he said about a 5 to 1 ratio. These are primarily wood frame houses with utilities coming from above ground electric poles. Think about the old movies where they would show lots of plugs and extension cords in older homes where there were not enough outlets. The outlets spark, overheat and cause fires. Plus, mice and other vermin in old homes can do real damage to electrical wires that are old and disintegrating.

I agree that things will radically change as we implement more efficient lighting and appliances. I have replaced nearly all the bulbs in our house with LED versions. A bulb that used to pull 100W now uses about 17W, doesn't get hot and lasts nearly forever. While not a true smart home, all our lamps plug into devices that we control over the internet.

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Re: Knob and Tube rewire cost

Post by doneat53 » Tue Aug 28, 2018 11:58 pm

I think your quote is somewhat typical although it is difficult for us to assess the complexity of your job. That said, 12k for rewire doesn't compare to the effort and time put into other projects in the house that go for much less. Take painting for example. Also, you should check to see if that quote includes plaster work, patching, and painting. Likely it doesn't so you'll be left with subcontracting a handyman to patch the holes they drilled to rewire after you pay them the 12k.

If you are handy you can do a lot of it yourself. Pulling the wire is the most difficult part and you could pull wire to the outlets, switches and lights and let the electrician hook it up and inspect it. This requires some knowledge of wire size, current loads, codes etc but most of it is common sense and easy math and there are plenty of books on the subject. Likely you will make fewer holes and take the time to finagle the wires to the switches etc so that patching will be minimized.

doneat

mancuso
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Re: Knob and Tube rewire cost

Post by mancuso » Wed Aug 29, 2018 12:18 am

doneat53 wrote:
Tue Aug 28, 2018 11:58 pm
If you are handy you can do a lot of it yourself. Pulling the wire is the most difficult part and you could pull wire to the outlets, switches and lights and let the electrician hook it up and inspect it. This requires some knowledge of wire size, current loads, codes etc but most of it is common sense and easy math and there are plenty of books on the subject.
The caveat here, if you are DIY'ing and intend to do it "to code" and particularly, to pull a city or county permit and have the work inspected, is to check both your overall system design (# of circuits, gauge of wire, type of breakers, etc.) AND the small details of materials & installation. If you live in a place with "loose" building inspectors (like I seem to, thankfully,) they will only point out very obvious/egregious mistakes or oversights. But some jurisdictions have *very* strict inspectors, where if you make one small error (for example, using the wrong kind of connector for the type of wire/cable you are using,) they will not let it pass & you will have to correct it.

If that error is one or two connections, hey, no problem you just fix it. But if you didn't check to be sure all the important stuff was correct before you did the work, and you repeated the same small error 100 or 200 times throughout the house you could be letting yourself in for many 10's to even 100's of hours of work to undo & correct it before you pass final inspection.

To some degree this problem is mitigated a little bit by the process of "rough / pre-final / final" inspections in the early, middle, and late phase of the work, but even so sometimes a simple oversight or lack of knowledge turns into tons of extra work. Take the time to do lots of homework and check your plans & installation details with your local building dept before you buy large amts. of material & start doing a lot of labor.

mancuso
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Re: Knob and Tube rewire cost

Post by mancuso » Wed Aug 29, 2018 12:24 am

NYnative wrote:
Tue Aug 28, 2018 11:39 pm
I have a simple answer as to why K&T should be replaced sooner, rather than later. It's called fire...

According to my nephew, electrical fires are far more common in houses with K&T wiring (or aluminum wiring) than those with modern, grounded circuitry and 200 amp panels. By far more common, he said about a 5 to 1 ratio.
Yes, the key issue with old K&T is that the asphalt-impregnated insulation becomes extremely brittle over time. It is generally safe "if in good condition and left undisturbed," but if there is any movement, particularly from small animals / vermin, or from human activity (say, in an attic) the insulation can crack off leaving sections of wire bare & inviting short-circuit hazards in the walls, attic, etc. Accumulation of decades of dust and lint in old, unsealed wall boxes doesn't help either.

A secondary issue is that the K&T wire gauge is typically smaller (seems to be around 16 AWG from what I've seen on the west coast,) which exacerbates heating problems from large current loads drawn by some modern appliances.

LED lighting does help a lot to reduce current loads , but that is only for the lighting circuits -- there are still plenty of power-hungry modern appliances, esp. in the kitchen & bathroom. (Toasters, hair dryers, heavy-duty food processors, 1800 watt microwave ovens, etc.)
----

Aluminum wiring is also a higher fire risk mainly because it is a lot harder to make a solid, long-term connection (splice) with it. The Al itself is not only a poorer conductor but it forms an oxide layer (think "aluminum rust") on its surface which is so non-conductive that the wire must be coated with copper in order to safely make connections (at least for small gauge wire, typically the #12 and #14AWG used in small residential work.) But aluminum has notoriously bad fatigue strength -- a very few bend cycles cause the metal to get brittle which tends to "crack" the copper coating & expose raw aluminum beneath. TL;DR Al wire is temperamental & tended to cause a lot of high-resistance splices, which led to higher rates of electrical fires, which caused its use to fall out of fashion.
Last edited by mancuso on Wed Aug 29, 2018 12:31 am, edited 1 time in total.

z0r
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Re: Knob and Tube rewire cost

Post by z0r » Wed Aug 29, 2018 12:37 am

mancuso wrote:
Tue Aug 28, 2018 11:05 pm
**Note that this is only safe if using generously-sized metal junction boxes which can easily dissipate any heat-build up through their walls. Plastic / fiberglass boxes require ventilation because they do not conduct heat well.
Can you give an NEC rule number or a link to manufacturer guidance for this?

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Re: Knob and Tube rewire cost

Post by mancuso » Wed Aug 29, 2018 2:25 am

z0r wrote:
Wed Aug 29, 2018 12:37 am
mancuso wrote:
Tue Aug 28, 2018 11:05 pm
**Note that this is only safe if using generously-sized metal junction boxes which can easily dissipate any heat-build up through their walls. Plastic / fiberglass boxes require ventilation because they do not conduct heat well.
Can you give an NEC rule number or a link to manufacturer guidance for this?
You've caught me without documentation or support for my opinion. I can't think of any applicable NEC citation which describes whether a residential electrical junction box may or may not be air-tight.

But certainly manufacturers of specific box models (both metal and plastic) most likely have opinions, and some of them may even prohibit sealing / caulking boxes for just that reason -- no air-flow = no possibility for convective air cooling.

My decision to do this is really a personal calculation based on my own good sense of "what's safe." If the power dissipation ( current x resistance) through the box is relatively low, and the box is thermally-conductive (i.e. made of metal) and is adequately capacious in size (= lots of surface area for dissipating heat,) then even an air-tight box will have no problems with internal heat build-up.

Where a problem would occur is if the box is nearly full (or over-filled) with splices / wires carrying a large amount of power.

In my personal case (residential,) on average I might have 2 circuits of max. 15 amps each in a 4 x 4 "deep" metal box (plus an additional 1/2 to 1" depth added by a metal mud ring.) All of this running on clean / new 12 AWG solid copper conductors.

For anyone considering doing similarly: do so at your own risk & check with the manufacturer, also check with your local jurisdiction. I use a UL-listed 3M firestopping product, "Fire Barrier Sealant CP 25WB+". I smear a generous layer all around the outside of the box & let it cure before installation. After the mud-ring goes on I use additional sealant (applied with a gloved finger) all around the inside seam/air gap between the mud ring & the box. Last, I seal the connectors where the cable(s) enter the box. When all is said & done and the finished box is mudded/sanded/painted, it's quite close to truly air-tight.

---

As I noted earlier, in my case my local building inspection dept. is pretty relaxed. During the rough inspection for my house rewiring many of my boxes were *bright blue* inside due to the application of lots of firestop. Nobody said anything to me about it, but as always YMMV.

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jharkin
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Re: Knob and Tube rewire cost

Post by jharkin » Wed Aug 29, 2018 7:52 am

I dont have much to comment on the price other than to say that 12k to require an entire house doesn't seem out of line, I paid $2500 just for a panel upgrade 10 years ago.

I suspect that your house is probably a bit older than you think it is however. KT wiring is not common after the 1930s, and the Bungalow style houses where mostly built during the Arts&Crafts/Craftwman Architecture era of the late 1890s though the late 1920s or so. Have you done a title search to find the original deed?

As you where told, K&T is safe to use provided:
#1 - its in good repair - the insulation is intact and all the porcelain knobs and tubes are in place and undamaged
#2 - It hasn't been modified and added on to.
#3 - Nobody has tried to blow insulation into the walls - this is one of the big fire dangers
#4- It hasn't been overloaded - i.e. if the panel has been replaced the original circuit ratings (sometimes as low as 10A) are maintained
#5 - You work within ts limitations - don't use any appliances rated higher than the above, and don't use anything that requires a ground (i.e. no cheater plugs and nothing that has a 3 prong plug)

I'm not surprised you got insured, my house is a lot older and had some remnant KT and we got insurance no problem... I ended up removing ht last of it early on because its just way undersized for modern uses and I wanted to insulate the house. I also removed some badly corroded BX (40s) and early cloth insulated ungrounded Romex (50s)
Last edited by jharkin on Wed Aug 29, 2018 8:30 am, edited 1 time in total.

Dottie57
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Re: Knob and Tube rewire cost

Post by Dottie57 » Wed Aug 29, 2018 8:09 am

wilked wrote:
Tue Mar 27, 2018 9:34 am
If you want any other electric changes, now is the time...

Things to consider -

1) New light switches, new dimmers, or moving light switches
2) Upgrade lights (recessed?), add a light, etc
3) New outlets, or upgrade 'two-prongers' to three
4) Demo out / remove unwanted outlets / outlets in weird locations
5) Misc changes (wire basement lights so all of them come on together with switch, etc)
6) Porch or outdoor lighting
7) "Enable" future electric car charging (upgrading to 200 amp prob all that's needed there)
+1

If you don’t have electricity in the garage now is a good time.

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runner9
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Re: Knob and Tube rewire cost

Post by runner9 » Wed Aug 29, 2018 9:49 am

OP here. Company took much longer than they thought, ended up with 10.5 working days over a few months, finally finishing in mid-July. With all that labor I think it was a great price, not sure they made much money.

I ended up with a ton of holes. Probably 70 I'm guessing. I've patched all myself, still need to figure out the ceiling texture and repaint a few rooms.

Our entire city was built in the early 1950s, I know for a fact when the house was built. I agree it's a little strange that everything has K&T when built in the 50s but that's for sure what happened.

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Re: Knob and Tube rewire cost

Post by spencnor » Thu Aug 30, 2018 5:26 pm

mancuso wrote:
Wed Aug 29, 2018 2:25 am
z0r wrote:
Wed Aug 29, 2018 12:37 am
mancuso wrote:
Tue Aug 28, 2018 11:05 pm
**Note that this is only safe if using generously-sized metal junction boxes which can easily dissipate any heat-build up through their walls. Plastic / fiberglass boxes require ventilation because they do not conduct heat well.
Can you give an NEC rule number or a link to manufacturer guidance for this?
You've caught me without documentation or support for my opinion. I can't think of any applicable NEC citation which describes whether a residential electrical junction box may or may not be air-tight.

But certainly manufacturers of specific box models (both metal and plastic) most likely have opinions, and some of them may even prohibit sealing / caulking boxes for just that reason -- no air-flow = no possibility for convective air cooling.

My decision to do this is really a personal calculation based on my own good sense of "what's safe." If the power dissipation ( current x resistance) through the box is relatively low, and the box is thermally-conductive (i.e. made of metal) and is adequately capacious in size (= lots of surface area for dissipating heat,) then even an air-tight box will have no problems with internal heat build-up.

Where a problem would occur is if the box is nearly full (or over-filled) with splices / wires carrying a large amount of power.

In my personal case (residential,) on average I might have 2 circuits of max. 15 amps each in a 4 x 4 "deep" metal box (plus an additional 1/2 to 1" depth added by a metal mud ring.) All of this running on clean / new 12 AWG solid copper conductors.

For anyone considering doing similarly: do so at your own risk & check with the manufacturer, also check with your local jurisdiction. I use a UL-listed 3M firestopping product, "Fire Barrier Sealant CP 25WB+". I smear a generous layer all around the outside of the box & let it cure before installation. After the mud-ring goes on I use additional sealant (applied with a gloved finger) all around the inside seam/air gap between the mud ring & the box. Last, I seal the connectors where the cable(s) enter the box. When all is said & done and the finished box is mudded/sanded/painted, it's quite close to truly air-tight.

---

As I noted earlier, in my case my local building inspection dept. is pretty relaxed. During the rough inspection for my house rewiring many of my boxes were *bright blue* inside due to the application of lots of firestop. Nobody said anything to me about it, but as always YMMV.
I don't want to be too technical here, but wanted to offer some guidance from my experience in the electrical industry. Manufacturers of electrical products, e.g., outlet or junction boxes, are required to comply with the National Electrical Code (NEC). NEC Section 314 covers box and wire fill calculations. Many DIY'ers miss the details of wire fill and junction box sizing and volume.

For energy saving reasons an electrical junction box may be sealed air tight. Note, except in classified hazardous locations, a junction box is not required to be air tight. Fire sealing of electrical boxes is required, however, to maintain a fire rating of of a fire rated wall, or partition. In a commercial setting there are generally 1, 2, and 4 hour fire rated walls. In a residential setting, there is generally a fire separation, not technically a fire rating, required for attached garages. The 3M product, Fire Barrier Modable Putty Pads, https://multimedia.3m.com/mws/media/201 ... -sheet.pdf is easier to apply to standard outlet boxes. Specifically refer to #6, Installation Techniques and Details.

Regarding plastic vs metal boxes and heat dissipation the National Electrical Code (NEC) doesn't make a distinction except that wire fill (box volume) must comply wit NEC Section 314. Specifically Table 314.16(A). See https://www.ecmweb.com/code-basics/box- ... lculations

As always consult your local electrical inspector, or licensed electrician if unsure about your wiring methods. :happy

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